U.S. patent application number 16/081109 was filed with the patent office on 2019-03-28 for rubber composition, laminated body, and conveyor belt.
This patent application is currently assigned to BRIDGESTONE CORPORATION. The applicant listed for this patent is BRIDGESTONE CORPORATION. Invention is credited to Shuyo AKAMA, Genho TAKANO, Youhei TSUNENISHI.
Application Number | 20190092932 16/081109 |
Document ID | / |
Family ID | 59744280 |
Filed Date | 2019-03-28 |
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United States Patent
Application |
20190092932 |
Kind Code |
A1 |
TAKANO; Genho ; et
al. |
March 28, 2019 |
RUBBER COMPOSITION, LAMINATED BODY, AND CONVEYOR BELT
Abstract
Provided is a high-productivity rubber composition having
excellent adhesiveness to a reinforcing member, particularly a
reinforcing member in environmental degradation, and capable of
bringing high peel operability therewith. The rubber composition is
obtainable by compounding a rubber component containing a diene
based rubber, a wet silica, a carbon black and a calcium carbonate,
wherein: a compounding amount of the wet silica is 3 parts by mass
or more and less than 5 parts by mass per 100 parts by mass of the
diene based rubber; and a compounding amount of the calcium
carbonate is 10 parts by mass or more and 120 parts by mass or less
per 100 parts by mass of the diene based rubber.
Inventors: |
TAKANO; Genho; (Yokohama,
JP) ; TSUNENISHI; Youhei; (Yokohama-shi, JP) ;
AKAMA; Shuyo; (Saitama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BRIDGESTONE CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
BRIDGESTONE CORPORATION
Tokyo
JP
|
Family ID: |
59744280 |
Appl. No.: |
16/081109 |
Filed: |
March 3, 2017 |
PCT Filed: |
March 3, 2017 |
PCT NO: |
PCT/JP2017/008576 |
371 Date: |
August 30, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 25/04 20130101;
C08L 7/00 20130101; B32B 7/12 20130101; C08K 3/26 20130101; C08K
3/36 20130101; C08K 3/04 20130101; C08K 2201/006 20130101; C08L
9/06 20130101; C08L 9/06 20130101; F16G 1/08 20130101; B65G 15/32
20130101; B65G 15/34 20130101; C08K 2003/265 20130101; C08K 3/36
20130101; C08L 7/00 20130101; C08L 9/00 20130101; C08K 3/26
20130101; C08K 3/04 20130101; C08L 9/00 20130101; C08L 9/00
20130101; C08K 3/04 20130101; C08K 3/26 20130101; C08K 3/36
20130101 |
International
Class: |
C08L 9/06 20060101
C08L009/06; C08L 7/00 20060101 C08L007/00; C08K 3/36 20060101
C08K003/36; C08K 3/26 20060101 C08K003/26; C08K 3/04 20060101
C08K003/04; B65G 15/34 20060101 B65G015/34 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 4, 2016 |
JP |
2016-041852 |
Claims
1. A rubber composition obtainable by compounding a rubber
component containing a diene based rubber, a wet silica, a carbon
black and a calcium carbonate, wherein: a compounding amount of the
wet silica is 3 parts by mass or more and less than 5 parts by mass
per 100 parts by mass of the diene based rubber; and a compounding
amount of the calcium carbonate is 10 parts by mass or more and 120
parts by mass or less per 100 parts by mass of the diene based
rubber.
2. The rubber composition according to claim 1, wherein: the
compounding amount of the wet silica is 4 parts by mass or more and
less than 5 parts by mass per 100 parts by mass of the diene based
rubber.
3. The rubber composition according to claim 1, wherein: the rubber
component contains a natural rubber and a styrene-butadiene
rubber.
4. The rubber composition according to claim 3, wherein: a ratio of
a compounding amount of the natural rubber to a total compounding
amount of the natural rubber and the styrene-butadiene rubber is 20
mass % or more and 60 mass % or less.
5. The rubber composition according to claim 1, wherein: a nitrogen
adsorption BET specific surface area of the wet silica is 80
m.sup.2/g or more.
6. The rubber composition according to claim 1, wherein: the
nitrogen adsorption BET specific surface area of the wet silica is
more than 200 m.sup.2/g.
7. The rubber composition according to claim 1, wherein: a nitrogen
adsorption BET specific surface area of the carbon black is 8
m.sup.2/g or more and 100 m.sup.2/g or less.
8. The rubber composition according to claim 1, wherein: the rubber
composition is used to be arranged between a rubber member and a
reinforcing member, or between reinforcing members, to adhere the
same.
9. A laminated body obtainable by laminating and adhering a layer
containing the rubber composition according to claim 1 and a
reinforcing member layer.
10. A conveyor belt comprising the laminated body according to
claim 9.
11. The conveyor belt according to claim 10, having a belt strength
of 80 N/mm or more and 3250 N/mm or less.
12. The conveyor belt according to claim 10, having a widthwise
length of 80 mm or more and 3200 mm or less.
13. The conveyor belt according to claim 10, having a longitudinal
length of 30 m or more.
14. The rubber composition according to claim 2, wherein: the
rubber component contains a natural rubber and a styrene-butadiene
rubber.
15. The rubber composition according to claim 2, wherein: a
nitrogen adsorption BET specific surface area of the wet silica is
80 m.sup.2/g or more.
16. The rubber composition according to claim 2, wherein: the
nitrogen adsorption BET specific surface area of the wet silica is
more than 200 m.sup.2/g.
17. The rubber composition according to claim 2, wherein: a
nitrogen adsorption BET specific surface area of the carbon black
is 8 m.sup.2/g or more and 100 m.sup.2/g or less.
18. The rubber composition according to claim 2, wherein: the
rubber composition is used to be arranged between a rubber member
and a reinforcing member, or between reinforcing members, to adhere
the same.
19. A laminated body obtainable by laminating and adhering a layer
containing the rubber composition according to claim 2 and a
reinforcing member layer.
20. The rubber composition according to claim 3, wherein: a
nitrogen adsorption BET specific surface area of the wet silica is
80 m.sup.2/g or more.
Description
TECHNICAL FIELD
[0001] This disclosure relates to a rubber composition, a laminated
body, and a conveyor belt.
BACKGROUND
[0002] For the purpose of reinforcing a rubber member to improve
strength thereof, reinforcing members, including an organic fiber
such as polyethylene terephthalate and nylon, which is untreated or
dipped with an adhesive component such as
resorcin-formaldehyde-latex (RFL), etc. on its surface, and/or an
inorganic fiber such as steel cord, and the like, are used for
rubber products required to have strength, such as tires for
automobiles, conveyor belts, and hoses.
[0003] In manufacture of such rubber product, such reinforcing
member and rubber member and/or such reinforcing members themselves
are occasionally adhered to one another through an adhesive
containing a rubber composition. For example, conveyor belts are
frequently used as item transportation means in various industrial
fields, and thus are required to have high durability capable of
withstanding friction and impact from transported items. Therefore,
they are ordinarily manufactured by: preparing one or more layers
of reinforcing member, and cover rubbers as rubber members;
laminating them via an adhesive containing a rubber composition
such that the cover rubbers become the upper and lower outermost
layers; and then performing vulcanization adhesion. In such
situation, in order to obtain high reinforcing effect, desired is a
rubber composition capable of exhibiting high adhesiveness between
reinforcing members and high adhesiveness between a rubber member
and a reinforcing member.
[0004] For example, in use of a conveyor belt, there are cases that
after manufacture of one layered belt including a layer containing
a rubber composition and a reinforcing member layer, a processing
(so-called endless processing) is performed to peel off a part of
the layers at both ends thereof, and to adhere the ends to each
other with an endless adhesive and/or an endless adhesive rubber,
etc. The adhered both ends (endless portion) are required to have
high durability in actual use, and it is particularly important
that the members in the endless portion, particularly the
reinforcing members, are firmly adhered.
[0005] Here, from a viewpoint of adhesiveness between a rubber
member using a rubber composition and a reinforcing member, for
example, JPH06-306211A (PTL1) discloses that a rubber
manufacturable from a rubber composition containing 0.5 parts to 10
parts by mass of N,N'-m-phenylene bismaleimide, 0.3 parts to 3
parts by mass of a carboxylic acid which is divalent or more or an
anhydride thereof, and 0.3 to 10 parts by mass of a compound that
generates formaldehyde when heated, per 100 parts by mass of a
rubber such as natural rubber and styrene butadiene rubber, has
excellent vulcanization adhesion performance to a reinforcing
member.
CITATION LIST
Patent Literature
[0006] PTL1: JPH06-306211A
SUMMARY
Technical Problem
[0007] However, our study discovered that there is a problem that
even if the aforementioned conventional rubber composition is
adhered to a reinforcing member, its adhesiveness is deteriorated
because of environmental degradation of the reinforcing member due
to transportation process, storage process, manufacture process,
etc. In particular, we discovered as well that in the case of
manufacturing a layered belt by laminating a plurality of layers
containing the aforementioned conventional rubber composition and
one or more of the reinforcing member layers, when its endless
portion is peeled off, its peel strength becomes insufficient, and
the amount of the rubber composition remaining on the reinforcing
members is small. Therefore, there is a risk that the reinforcing
members are not adhered to one another firmly enough, and are
incapable of bringing high durability to the conveyor belt, which
leaves room for improving such rubber composition.
[0008] On the other hand, when performing an operation peeling off
a layer containing a rubber composition from a reinforcing member
layer, such as the aforementioned endless processing, it is
important that peel can be performed readily at some degree, and
the aforementioned conventional rubber composition is required to
have high peel operability as well.
[0009] It thus would be helpful to provide a high-productivity
rubber composition having excellent adhesiveness to a reinforcing
member, particularly a reinforcing member in environmental
degradation, capable of bringing high peel operability therewith.
It would also be helpful to provide a high-productivity laminated
body using the aforementioned rubber composition and capable of
improving durability of a rubber product, and a high-productivity
conveyor belt using the aforementioned laminated body and having
high durability.
Solution to Problem
[0010] As a result of intensive study in order to achieve the
aforementioned purpose, we discovered that by compounding a
specific compound at a specific amount to a rubber component
containing a diene based rubber, it is possible to obtain, at a
high productivity, a rubber composition having excellent
adhesiveness to a reinforcing member, particularly a reinforcing
member in environmental degradation, and capable of bringing high
peel operability therewith.
[0011] The disclosed rubber composition is a rubber composition
obtainable by compounding a rubber component containing a diene
based rubber, a wet silica, a carbon black and a calcium carbonate,
wherein:
[0012] a compounding amount of the wet silica is 3 parts by mass or
more and less than 5 parts by mass per 100 parts by mass of the
diene based rubber; and
[0013] a compounding amount of the calcium carbonate is 10 parts by
mass or more and 120 parts by mass or less per 100 parts by mass of
the diene based rubber.
[0014] The disclosed laminated body is obtainable by laminating and
adhering a layer containing the disclosed rubber composition and a
reinforcing member layer.
[0015] The disclosed conveyor belt contains the disclosed laminated
body.
Advantageous Effect
[0016] According to this disclosure, it is possible to provide a
high-productivity rubber composition having excellent adhesiveness
to a reinforcing member, particularly a reinforcing member in
environmental degradation, and capable of bringing high peel
operability therewith. Further, according to this disclosure, it is
possible to provide a high-productivity laminated body using the
aforementioned rubber composition and capable of improving
durability of a rubber product, and a high-productivity conveyor
belt using the aforementioned laminated body and having high
durability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the accompanying drawings:
[0018] FIGS. 1A and 1B schematically illustrate a peeled surface in
a peel test on a layer containing the disclosed rubber composition
and a reinforcing member layer;
[0019] FIGS. 2A and 2B schematically illustrate a peeled surface in
a peel test on a layer containing a rubber composition of a
comparative example and a reinforcing member layer; and
[0020] FIGS. 3A and 3B schematically illustrate a peeled surface in
a peel test on a layer containing a rubber composition of another
comparative example and a reinforcing member layer.
DETAILED DESCRIPTION
[0021] <Rubber Composition>
[0022] The following describes one of the disclosed embodiments in
detail.
[0023] The disclosed rubber composition is obtainable by
compounding at least a rubber component containing a diene based
rubber, a wet silica, a carbon black and a calcium carbonate, and
further compounding other components if necessary.
[0024] (Rubber Component)
[0025] The disclosed rubber composition needs to contain a diene
based rubber as a rubber component. The diene based rubber is
capable of exhibiting performances such as high elasticity and high
heat resistance via vulcanization. The diene based rubber is not
specifically limited and may be appropriately selected depending on
the purpose. Examples include natural rubber (NR); and diene based
synthetic rubbers such as butadiene rubber (BR), styrene-butadiene
rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR),
ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene
rubber (NBR) and butyl rubber (IIR). These may be used singly or in
combination of two or more.
[0026] In particular, the disclosed rubber composition preferably
contains a natural rubber and a styrene-butadiene rubber, from a
viewpoint of improving adhesiveness to a reinforcing member.
[0027] In the case where the disclosed rubber composition contains
a diene based synthetic rubber such as styrene-butadiene rubber, a
cis-1,4 bond content in a diene monomer unit constituting the
synthetic rubber is preferably 98% or less, and more preferably 90%
or less, from a viewpoint of adhesiveness, and a viewpoint of
obtaining appropriate operability without excessively high
viscosity during processing in an unvulcanized state. Such cis-1,4
bond content may be measured by using, for example, .sup.1H-NMR
spectrum and .sup.13C-NMR spectrum.
[0028] The ratio of the diene based rubber in the rubber component
of the disclosed rubber composition is not specifically limited and
may be appropriately selected depending on the purpose, but is
preferably 80 mass % or more, more preferably 90 mass % or more,
particularly preferably 100 mass %. The ratio of the diene based
rubber in the rubber component of 80 mass % or more improves
adhesiveness between the obtained rubber composition and a
reinforcing member is improved, improves durability of a rubber
product using a laminated body of a layer containing the rubber
composition and a reinforcing member layer.
[0029] In the case of using both a natural rubber and a
styrene-butadiene rubber as the diene based rubber, the ratio of
the compounding amount of the natural rubber to the total
compounding amount of the natural rubber and the styrene-butadiene
rubber is preferably 20 mass % or more, and preferably 60 mass % or
less. The ratio of the compounding amount of the natural rubber of
20 mass % or more improves the mechanical strength of a rubber
member or rubber product using the obtained rubber composition, and
on the other hand, the ratio of the compounding amount of the
natural rubber of 60 mass % or less improves wear resistance and
film thickness stability of a rubber member or rubber product using
the obtained rubber composition. From the same viewpoint, the ratio
of the compounding amount of the natural rubber to the total
compounding amount of the natural rubber and the styrene-butadiene
rubber is more preferably 30 mass % or more, and more preferably 50
mass % or less.
[0030] Moreover, in the case of using both a natural rubber and a
styrene-butadiene rubber as the diene based rubber, the ratio of
the compounding amount of the styrene-butadiene rubber to the total
compounding amount of the natural rubber and the styrene-butadiene
rubber is preferably 40 mass % or more, and preferably 80 mass % or
less. The ratio of the compounding amount of the styrene-butadiene
rubber of 40 mass % or more improves aging resistance of a rubber
member or rubber product using the obtained rubber composition, and
on the other hand, the ratio of the compounding amount of the
styrene-butadiene rubber of 80 mass % or less improves flex
cracking resistance of a rubber member or rubber product using the
obtained rubber composition. From the same viewpoint, the ratio of
the compounding amount of the styrene-butadiene rubber to the total
compounding amount of the natural rubber and the styrene-butadiene
rubber is more preferably 50 mass % or more, and more preferably 70
mass % or less.
[0031] Other than the diene based rubber, the disclosed rubber
composition may also contain a non-diene based rubber (a rubber
component other than diene based rubber) as the rubber component,
and may use a non-diene based rubber ordinarily used in rubber
products without being specifically limited. Moreover, in the
disclosed rubber composition, a reclaimed rubber containing a diene
based rubber and optionally a non-diene based rubber may be used.
In the case of using a reclaimed rubber in the disclosed rubber
composition, the compounding amount of the reclaimed rubber may
preferably be determined such that a polymer component in the
reclaimed rubber is 20 mass % or less with respect to the total
amount of compounded polymers, from a viewpoint of sufficiently
ensuring quality of a rubber product using the obtained rubber
composition.
[0032] (Wet Silica)
[0033] The disclosed rubber composition needs to contain a wet
silica. The wet silica may be obtained by, for example, using
sodium silicate as a raw material, neutralizing its water solution
to precipitate silica, filtering, and drying. The wet silica is
classified into precipitated silica and gel process silica, both of
which may be used. By using the wet silica in the rubber
composition, it is possible to improve adhesiveness between such
rubber composition and a reinforcing member such as organic fiber,
particularly a reinforcing member in environmental degradation. The
reason has not been clarified, but it is considered that the unique
high polarity of wet silica contributes to improvement of
adhesiveness. The wet silica may be used singly or in combination
of two or more.
[0034] The nitrogen adsorption BET specific surface area
(N.sub.2SA) of the wet silica used in the disclosed rubber
composition is not specifically limited and may be appropriately
selected depending on the purpose, but is preferably 80 m.sup.2/g
or more. The nitrogen adsorption BET specific surface area of the
wet silica of 80 m.sup.2/g or more raises polarity of the rubber
composition, further improves adhesiveness between the rubber
composition and a reinforcing member, and suppresses deterioration
of the peel operability when peeling off a layer containing this
rubber composition from a reinforcing member layer in environmental
degradation. From the same viewpoint, the nitrogen adsorption BET
specific surface area of the wet silica is more preferably 120
m.sup.2/g or more, even more preferably more than 150 m.sup.2/g,
further preferably more than 200 m.sup.2/g.
[0035] The nitrogen adsorption BET specific surface area of the wet
silica may be measured according to ISO5794-1.
[0036] The average primary particle size of the wet silica used in
the disclosed rubber composition is not specifically limited and
may be appropriately selected depending on the purpose, but is
preferably 10 nm or more. The average primary particle size of the
wet silica of 10 nm or more suppresses reduction of the
productivity due to scattering, etc. during kneading.
[0037] The average primary particle size of the wet silica may be
determined via calculation by using, for example, transmission
electron microscope electron microscope image and/or BET specific
surface area. Examples of the method for calculating the BET
specific surface area include conventionally well-known methods,
such as "Nanomaterial Information Provision Sheet: Amorphous
Colloidal Silica (as of March, 2011) Reference 6." published by
METI.
[0038] The compounding amount of the wet silica in the disclosed
rubber composition is not specifically limited as long as it is 3
parts by mass or more and less than 5 parts by mass per 100 parts
by mass of the diene based rubber, but is preferably 4 parts by
mass or more. If the compounding amount of the wet silica in the
rubber composition is less than 3 parts by mass per 100 parts by
mass of the diene based rubber, there is a risk that the
improvement effect of adhesiveness to a reinforcing member due to
the compounded wet silica, particularly a reinforcing member
degraded due to exposure to atmosphere, is insufficient. The
compounding amount of the wet silica in the rubber composition of 4
parts by mass or more per 100 parts by mass of the diene based
rubber obtains a rubber composition with sufficiently high
adhesiveness to a reinforcing member, particularly a reinforcing
member degraded due to exposure to atmosphere. On the other hand,
the compounding amount of the wet silica in the rubber composition
of 5 parts by mass or more per 100 parts by mass of the diene based
rubber excessively increases the time needed for vulcanization of
the rubber composition, which deteriorates productivity.
[0039] (Carbon Black)
[0040] The disclosed rubber composition needs to contain a carbon
black. The carbon black, as a reinforcing filler, has a function of
improving the modulus and the wear resistance of the rubber
composition, and appropriately improving adhesiveness between this
rubber composition and a reinforcing member, particularly a
reinforcing member in environmental degradation. The carbon black
may be used singly or in combination of two or more.
[0041] The nitrogen adsorption BET specific surface area
(N.sub.2SA) of the carbon black used in the disclosed rubber
composition is not specifically limited and may be appropriately
selected depending on the purpose, but is preferably 8 m.sup.2/g or
more, and preferably 100 m.sup.2/g or less. The nitrogen adsorption
BET specific surface area of the carbon black of 8 m.sup.2/g or
more ensures the peel strength between the rubber composition and a
reinforcing member, particularly a reinforcing member in
environmental degradation, and ensures sufficient reinforcement
performance. Moreover, the nitrogen adsorption BET specific surface
area of the carbon black of 100 m.sup.2/g or less sufficiently
suppresses deterioration of peel operability when peeling off a
layer containing this rubber composition from a reinforcing member
layer, obtains sufficient productivity such as scattering
resistance and rollability during manufacture, and simultaneously
ensures high dispersibility in the rubber composition during
kneading. From the same viewpoint, the nitrogen adsorption BET
specific surface area of the carbon black is more preferably 25
m.sup.2/g or more, and more preferably 90 m.sup.2/g or less.
[0042] The nitrogen adsorption BET specific surface area of the
carbon black may be measured with, for example, a conventionally
publicly-known method.
[0043] The compounding amount of the carbon black in the disclosed
rubber composition is not specifically limited and may be
appropriately selected depending on the purpose, but is preferably
10 parts by mass or more and preferably 100 parts by mass or less
per 100 parts by mass of the diene based rubber. The compounding
amount of the carbon black in the rubber composition of 10 parts by
mass or more per 100 parts by mass of the diene based rubber
suppresses deterioration of the peel strength between this rubber
composition and a reinforcing member, particularly a reinforcing
member in environmental degradation. Moreover, the compounding
amount of the carbon black in the rubber composition of 100 parts
by mass or less per 100 parts by mass of the diene based rubber
improves the operability when peeling off a layer containing this
rubber composition from a reinforcing member layer, for example,
during endless processing of the conveyor belt. From the same
viewpoint, the compounding amount of the carbon black in the rubber
composition is more preferably 30 parts by mass or more, and more
preferably 50 parts by mass or less per 100 parts by mass of the
diene based rubber.
[0044] In the disclosed rubber composition, the total compounding
amount of the aforementioned wet silica and carbon black is
preferably 30 parts by mass or more, and preferably 80 parts by
mass or less per 100 parts by mass of the diene based rubber. The
total compounding amount of the wet silica and the carbon black of
30 parts by mass or more per 100 parts by mass of the diene based
rubber obtains a rubber composition with excellent peel strength
with a reinforcing member, particularly a reinforcing member
degraded due to exposure to atmosphere, and sufficiently high
adhesiveness to the reinforcing member. Moreover, the total
compounding amount of the wet silica and the carbon black of 80
parts by mass or less per 100 parts by mass of the diene based
rubber suppresses reduction of the productivity of a rubber product
using such rubber composition due to excessively long time needed
for vulcanization, and suppresses deterioration of the operability
when peeling off a layer containing this rubber composition from a
reinforcing member layer, for example, during endless processing of
the conveyor belt. From the same viewpoint, the total compounding
amount of the wet silica and the carbon black in the rubber
composition is more preferably 40 parts by mass or more, and more
preferably 55 parts by mass or less per 100 parts by mass of the
diene based rubber.
[0045] (Calcium Carbonate)
[0046] The disclosed rubber composition needs to contain a calcium
carbonate. The calcium carbonate has a function of reducing
breaking resistance of the rubber composition to thereby improve
adhesiveness of the rubber composition with a reinforcing member
such as organic fibers and other rubber members, and has a function
of improving the peel operability of the rubber composition and the
reinforcing member. The calcium carbonate may be used singly or in
combination of two or more.
[0047] The average primary particle size of the calcium carbonate
used in the disclosed rubber composition is not specifically
limited and may be appropriately selected depending on the purpose,
but is preferably 0.5 .mu.m or more. The average primary particle
size of the calcium carbonate of 0.5 .mu.m or more sufficiently
improves adhesiveness between the rubber composition and a
reinforcing member, particularly a reinforcing member in
environmental degradation.
[0048] Moreover, the average primary particle size of the calcium
carbonate is more preferably 0.8 .mu.m or more, and more preferably
13 .mu.m or less. The average primary particle size of the calcium
carbonate of 0.8 .mu.m or more suppresses rise of viscosity of
unvulcanized rubber composition, and brings stable film thickness
stability. Moreover, the average primary particle size of the
calcium carbonate of 13 .mu.m or less suppresses deterioration of
the modulus and tear strength of vulcanized rubber composition,
obtains stable reinforcing effect, and improves the peel strength.
From the same viewpoint, the average primary particle size of the
calcium carbonate is more preferably 1.0 .mu.m or more, further
more preferably 2.0 .mu.m or more, and more preferably 12.0 .mu.m
or less.
[0049] The average primary particle size of the calcium carbonate
may be measured by, for example, observing with a scanning electron
microscope.
[0050] The calcium carbonate used in the disclosed rubber
composition may use a calcium carbonate subjected to surface
treatment by using an organic material if necessary, in order to
obtain excellent dispersity in the rubber composition.
[0051] The compounding amount of the calcium carbonate in the
disclosed rubber composition needs to be 10 parts by mass or more
and 120 parts by mass or less per 100 parts by mass of the diene
based rubber. If the compounding amount of the calcium carbonate in
the rubber composition is less than 10 parts by mass per 100 parts
by mass of the diene based rubber, there is a risk of cost increase
of the rubber composition, a risk of deterioration of the
operability due to close contact with a bumbary, a roll, etc.
caused by excessively low viscosity of unvulcanized rubber
composition, and a risk of deterioration of the operability when
peeling off the rubber composition from the reinforcing member due
to excessively high cohesion tearing force of the rubber
composition. Further, if the compounding amount of the calcium
carbonate in the rubber composition is more than 120 parts by mass
per 100 parts by mass of the diene based rubber, there is a risk of
excessive decrease of a cohesion tearing force of the rubber
composition and insufficient peel strength between the rubber
composition and a reinforcing member, a risk of deterioration of
the productivity during rolling which uses a roll due to
unvulcanized rubber composition floating from a roll and thus is
not provided with sufficient shearing heat, and a risk of
insufficient dispersity in the rubber composition during kneading
using a Banbury mixer, a Brabender mixer, a kneader, etc. From the
same viewpoint, the compounding amount of the calcium carbonate in
the rubber composition is preferably 20 parts by mass or more, and
preferably 100 parts by mass or less.
[0052] (Other Components)
[0053] In the disclosed rubber composition, other than the
aforementioned rubber component, wet silica, carbon black and
calcium carbonate, compounding ingredients ordinarily used in the
rubber industry, for example, a vulcanizing agent such as sulfur, a
vulcanization accelerator, a vulcanization accelerator aid such as
zinc oxide, a softener, an age resistor, an antiscorching agent, a
processing aid, a lubricant, a silica other than the aforementioned
wet silica such as dry silica, a filler other than carbon black and
calcium carbonate, a filler modifier, a tackifier, a colorant, etc.
may be used appropriately depending on the purpose.
[0054] In the case of using sulfur as a vulcanizing agent to the
disclosed rubber composition, its compounding amount is preferably
1.5 parts by mass or more and 3 parts by mass or less per 100 parts
by mass of the diene based rubber, from a viewpoint of effectively
vulcanization at a minimum necessary amount.
[0055] (Preparation of Rubber Composition)
[0056] The disclosed rubber composition may be prepared by, for
example, kneading the aforementioned components by using a Banbury
mixer, a Brabender mixer, a kneader, etc.
[0057] A rubber composition prepared in this way has the following
features. Namely, in the case of adhering such rubber composition
and a reinforcing member, particularly a reinforcing member in
environmental degradation, and then peeling off the same, it is
possible to obtain high peel strength. Moreover, in the case of
adhering such rubber composition and a reinforcing member,
particularly a reinforcing member in environmental degradation, and
then peeling off the same, the amount of the rubber composition
remaining on the reinforcing member is more. Further, due to these
features, the disclosed rubber composition can be said as having
excellent adhesiveness to a reinforcing member such as organic
fibers, particularly a reinforcing member in environmental
degradation, and may be preferably used in manufacture of rubber
products such as tires for automobiles, conveyor belts, and hoses.
Specifically, when manufacturing a rubber product, it is possible
to arrange this rubber composition between reinforcing members, or
between a rubber member and a reinforcing member, to firmly adhere
these members. In other words, the disclosed rubber composition may
be used as an adhesive rubber composition. This rubber composition
may be used, for example, to a conveyor belt in a layered shape, by
laminating with reinforcing member layers. Furthermore, during
endless processing of such conveyor belt, after peeling off
reinforcing members from each other or peeling off a rubber member
from a reinforcing member adhered by the aforementioned rubber
composition, and then re-adhering these by using a rubber for
endless adhesion, it is possible to perform firm adhesion.
[0058] The "rubber member" herein refers to any member containing
at least a rubber component for use in manufacture of a rubber
product.
[0059] <Laminated Body>
[0060] The disclosed laminated body is obtainable by laminating and
adhering at least a layer containing the disclosed rubber
composition (hereinafter also referred to as "the present rubber
composition layer") and a reinforcing member layer to each other.
In other words, the disclosed laminated body is obtainable by
laminating and adhering the present rubber composition layer and
the reinforcing member layer to each other. Such laminated body has
the layer containing the rubber composition and the reinforcing
member layer, which are firmly adhered to each other, and thus is
capable of improving durability of a rubber product, and has high
productivity. The disclosed laminated body is inclusive of a
laminated body obtainable by alternately laminating and adhering a
plurality of the present rubber composition layers and one or a
plurality of the reinforcing member layers to one another, and is
also inclusive of a laminated body obtainable by laminating and
adhering the present rubber composition layer onto both sides of a
reinforcing member layer, and further laminating two or more of a
product obtained thereby. Moreover, in addition to a layer
containing the disclosed rubber composition, the disclosed
laminated body may also include a rubber layer other than a layer
containing the disclosed rubber composition.
[0061] (The Present Rubber Composition Layer)
[0062] The present rubber composition layer may be one obtainable
by shaping the disclosed rubber composition into a sheet-like shape
by using an apparatus such as a rolling roll and an extruder.
[0063] The thickness of the present rubber composition layer is not
specifically limited and may be appropriately selected depending on
the purpose, but is preferably 0.2 mm or more and 2 mm or less,
from a viewpoint of suppression of rubber breakage during molding,
and a viewpoint of thinning. In the case of using a plurality of
the present rubber composition layers, thickness of each present
rubber composition layer may be either identical or different.
[0064] (Reinforcing Member Layer)
[0065] The reinforcing member layer has a function of improving the
reinforcement performance of rubber products such as tires for
automobiles, conveyor belts, and hoses. Here, the reinforcing
member layer is not particularly limited and may be appropriately
selected depending on the purpose. The reinforcing member layer as
an adhesion target of the present rubber composition layer is
particularly preferably a layer including an organic fiber
(hereinafter also referred to as "organic fiber layer"), more
preferably a canvas layer formed of an organic fiber. The term
"canvas" herein refers to a textile obtained by weaving fibers.
[0066] The material of the organic fiber is not specifically
limited and may be appropriately selected depending on the purpose.
Examples include fibers formed of aliphatic polyamides such as
nylon; aromatic polyamides such as Kevlar; polyesters such as
polyethylene terephthalate, polyethylene naphthalate, polyethylene
succinate and polymethyl methacrylate;
syndiotactic-1,2-polybutadiene; acrylonitrile-butadiene-styrene
copolymer; polystyrene; and copolymers thereof. These may be used
singly or in combination of two or more. For example, in the case
of using a canvas formed of an organic fiber as the reinforcing
member layer, warp and woof yarns of the canvas may be formed of
different materials.
[0067] The reinforcing member layer may be an untreated organic
fiber layer, but adhesiveness is preferably one including on at
least a part of its surface, for example, its entire surface, a
film containing resorcinol, formaldehyde, a condensate of
resorcinol and formaldehyde, and a latex (hereinafter also referred
to as "RFL film"), from a viewpoint of improving adhesiveness
between the present rubber composition layer and the reinforcing
member layer.
[0068] The RFL film may be obtained by, for example, before
laminating with the present rubber composition layer, immersing at
least a part of the organic fiber, for example, the entire organic
fiber, in a liquid containing resorcinol, formaldehyde, a partial
condensate of resorcinol and formaldehyde, and a latex (hereinafter
also referred to as "RFL dispersion"), and subjecting the same to
heat treatment. Moreover, the partial condensate of resorcinol and
formaldehyde may be obtained via resolification reaction. From a
viewpoint of improving adhesiveness between the present rubber
composition layer and the reinforcing member layer, examples of the
latex to be contained in the RFL dispersion include vinyl pyridine
latex, styrene-butadiene copolymer latex (SBR latex), natural
rubber latex, acrylate copolymer based latex, butyl rubber latex,
nitrile rubber latex, and chloroprene latex. These may be used
singly or in combination of two or more.
[0069] When preparing the RFL dispersion, reaction catalysts such
as acids and alkalis may be used together if necessary.
[0070] A mass ratio of the resorcinol, the formaldehyde, the
partial condensate of resorcinol and formaldehyde, to the latex in
the RFL dispersion is not specifically limited.
[0071] Specifically, the RFL film may be obtained by immersing a
part or an entire organic fiber such as a canvas in the
aforementioned RFL dispersion, removing extra attached liquid by
passing the same between rolls or performing vacuum suction if
necessary, and then performing one-phase or multiphase heat
treatment.
[0072] Here, in order to accelerate the reaction and to reduce heat
shrinkage in actual use, a final treatment temperature in the heat
treatment is preferably 180.degree. C. or higher, particularly
preferably 200.degree. C. or higher.
[0073] (Rubber Layer Other than the Present Rubber Composition
Layer)
[0074] Moreover, the disclosed laminated body may include a rubber
layer other than the present rubber composition layer on at least
one outermost layer depending on the requirement of the desired
rubber product. For example, in the case of using the disclosed
laminated body to a conveyor belt, the laminated body may include
on the outermost layer a rubber layer capable of functioning as a
cover rubber. Here, the rubber layer capable of functioning as a
cover rubber is not specifically limited. Examples thereof may be
obtained by appropriately kneading: a polymer component containing
a natural rubber (NR), a butadiene rubber (BR), a styrene-butadiene
rubber (SBR), an isoprene rubber (IR), a chloroprene rubber (CR),
an ethylene-propylene-dine rubber (EPDM), an
acrylonitrile-butadiene rubber (NBR), a butyl rubber (IIR), etc.,
or a mixture thereof; and a vulcanizing agent such as sulfur, a
vulcanization accelerator, a vulcanization accelerator aid such as
zinc oxide, a softener, an age resistor, an antiscorching agent, a
processing aid, a lubricant, a carbon black, a silica, calcium
carbonate a filler modifier, a tackifier, a colorant, etc.
depending on the purpose. Examples of the cover rubber include an
upper cover rubber and a lower cover rubber, which may be rubber
members of either the same type or different types.
[0075] In the case where the disclosed laminated body includes on
the outermost layer a rubber layer other than the present rubber
composition layer, such rubber layer is preferably adjacent on its
inner side to the present rubber composition layer.
[0076] (Preparation of Laminated Body)
[0077] The method for laminating the present rubber composition
layer, the reinforcing member layer, and optionally a rubber layer
other than the present rubber composition layer is not specifically
limited, and an ordinary method may be used for laminating.
[0078] Here, in the case of laminating with a conventionally known
calendering process by using the present rubber composition layer
and the reinforcing member layer, a laminated body A may first be
manufactured, which includes a rubber composition layer--a
reinforcing member layer--a rubber composition layer. This
laminated body A may be directly used. Alternatively, two or more
of the laminated bodies A may be laminated to one another so as to
be used as use a laminated body B, depending on necessary
properties of the rubber product such as conveyor belt (namely, the
laminated body B will include [a rubber composition layer--a
reinforcing member layer--a rubber composition layer--a rubber
composition layer--a reinforcing member layer--a rubber composition
layer] when formed by stacking two of the laminated bodies A to
each other). Furthermore, for example, in manufacture of the
conveyor belt, by laminating the aforementioned rubber layer
capable of functioning as a cover rubber to the outermost surface
of the laminated body A or of the laminated body B with an ordinary
method, it is possible to prepare the disclosed laminated body.
Examples of the aforementioned laminated body B used in manufacture
of the conveyor belt may be obtained by overlapping two to eight
laminated bodies A.
[0079] The method for adhering the laminated present rubber
composition layer and the reinforcing member layer, and optionally
the present rubber composition layer and a rubber layer other than
the present rubber composition layer, is not specifically limited.
Examples thereof include: a method of arranging the laminated
rubber composition layer and reinforcing member layer, and
optionally a rubber layer other than the present rubber composition
layer, in a predetermined mold, and adhering via vulcanization (the
so-called vulcanization molding).
[0080] The temperature of vulcanization is not specifically limited
and may be appropriately selected depending on the purpose, but is
preferably in a range of 130.degree. C. to 170.degree. C. from a
viewpoint of sufficiently adhering the present rubber composition
layer and the reinforcing member layer to each other, and
simultaneously suppressing overvulcanization. Moreover, the
vulcanization time is not specifically limited, but is preferably
set appropriately so as to sufficiently conduct heat to the center
of the laminate to perform vulcanization, in order to sufficiently
adhere the present rubber composition layer and the reinforcing
member layer to each other.
[0081] The laminated body prepared in this way has the present
rubber composition layer and the reinforcing member layer, and
optionally the present rubber composition layer and a rubber layer
other than the present rubber composition layer, which are firmly
adhered to each other, and thus is capable of improving the
durability of a rubber product when used as a member of the rubber
product, and may be preferably used as a member of rubber products
required to have high durability, such as tires for automobiles,
conveyor belts, and hoses. Such laminated body can be manufactured
by using the disclosed rubber composition, and thus has high
productivity.
[0082] <Conveyor Belt>
[0083] The disclosed conveyor belt contains the aforementioned
disclosed laminated body. The disclosed conveyor belt is not
specifically limited as long as the disclosed laminated body is
used therefor.
[0084] As mentioned above, in the disclosed conveyor belt, the
present rubber composition layer and the reinforcing member, and
optionally the present rubber composition layer and a rubber layer
other than the present rubber composition layer, are firmly adhered
to each other, and thus the disclosed conveyor belt has high
durability. Moreover, for the same reason, the disclosed conveyor
belt has high reinforcement performance as well. Further, the
disclosed conveyor belt can be manufactured by using the disclosed
laminated body, and thus has high productivity.
[0085] The disclosed conveyor belt has a belt strength of
preferably 80 N/mm or more, and preferably 3250 N/mm or less, from
a viewpoint of durability, etc.
[0086] The "belt strength" of the conveyor belt herein refers to a
tensile strength per unit width (unit: N/mm) of the belt main body
(exclusive of the endless portion).
[0087] The disclosed conveyor belt has a widthwise (minor axis
direction) length of preferably 80 mm or more, and preferably 3200
mm or less.
[0088] Further, the disclosed conveyor belt has a longitudinal
(major axis direction) length of preferably 30 m or more.
EXAMPLES
[0089] The following describes the presently disclosed tire in more
detail through examples. However, the presently disclosed tire is
not in any way limited by the following examples and suitable
alterations may be made that do not change the essence thereof.
[0090] <Preparation of Rubber Composition>
[0091] A Banbury mixer is used to prepare an unvulcanized rubber
composition through addition of: a processing aid, a lubricant,
sulfur, a vulcanization accelerator and zinc oxide to the
formulation as listed in Tables 1 to 4 (unit: parts by mass) at
amounts selected according to an ordinary method.
[0092] By using the prepared unvulcanized rubber composition,
evaluation of vulcanization time and film thickness stability was
performed according to the following procedure (evaluation of film
thickness stability was performed to only Examples 21 to 24).
[0093] (Measurement of 90% Vulcanization Time)
[0094] A block-shaped unvulcanized rubber composition cut into a
weight of 8.+-.1 g was used as a sample. By using this sample, its
90% vulcanization time (tc(90)) at 155.degree. C. was determined
with a Curelastometer ("CURELASTOMETER7", manufactured by JSR
corporation) according to JIS K6300-2 and ISO6502. The
vulcanization time was evaluated as follows. A smaller measurement
indicates a shorter vulcanization time of the rubber
composition.
[0095] --Evaluation of Vulcanization Time-- [0096] More than 7.0
minutes . . . poor [0097] 5.0 minutes or more and 7.0 minutes or
less . . . good [0098] Less than 5.0 minutes . . . excellent
[0099] (Evaluation of Film Thickness Stability)
[0100] An unvulcanized rubber composition in a sheet-like shape
with a thickness of 0.7 mm, which was manufactured by using a
6-inch diameter rolling roll (corresponding to the following rubber
composition layer mentioned below), was shaped into a shape with a
width of 25 cm to 30 cm and a length of 40 cm to 100 cm as a
sample. After drawing a square block which is 20 cm on each side
centering on a center of this sheet-like sample, each thickness at
each apex, midpoints of each side and a central point (9 points in
total) of this square block was measured by using a digital
thickness gauge ("SMD-550S2-LW", manufactured by Teclock
Corporation). Then, differences between maximum values and minimum
values of the thickness at the aforementioned 9 points were
calculated and evaluated according to the following standard.
[0101] Difference between maximum value and minimum value of
thickness is less than 0.03 mm . . . excellent
[0102] Difference between maximum value and minimum value of
thickness is 0.03 mm or more and less than 0.06 mm . . . good
[0103] Difference between maximum value and minimum value of
thickness is 0.06 mm or more . . . poor
[0104] <Preparation of Reinforcing Member Layer>
[0105] A piece of canvas cloth including warp yarns formed of
polyethylene terephthalate (number of twist: 16 T/10 cm, number of
yarn: 83/5 cm) and woof yarns formed of nylon (number of twist: 12
T/10 cm, number of yarn: 32/5 cm) was prepared. On the other hand,
resorcinol, formalin, water and an alkaline reaction catalyst, were
sequentially mixed and stirred, so as to partially proceed a
condensation reaction of resorcinol and formaldehyde, and then an
SBR latex, a vinyl pyridine latex and water were mixed and stirred,
to thereby prepare an RFL dispersion. Then, the aforementioned
piece of canvas cloth was entirely immersed in the RFL dispersion
thus obtained. The immersed piece of canvas cloth was subjected to
drying and heat treatment until the final treatment temperature
fell within a range of 210.degree. C. to 240.degree. C., and an
"undegraded reinforcing member layer" including an RFL film on its
surface was obtained. When forming the RFL film in the undegraded
reinforcing member layer, the RFL dispersion was adjusted until a
latex concentration in terms of the SBR latex and the vinyl
pyridine latex in the RFL film in total became 83 mass %.
[0106] Further, an undegraded reinforcing member layer the same as
the above was prepared, and was left standing for 60 minutes in an
ozone tank at 40.degree. C. and an ozone concentration of 50 pphm,
to obtain a "degraded reinforcing member layer".
[0107] <Preparation of Laminated Body Sample>
[0108] By using the aforementioned unvulcanized rubber composition,
a rubber composition layer with a thickness of 0.7 mm was
manufactured with a 6-inch diameter rolling roll. Next, by using
this rubber composition layer and the aforementioned reinforcing
member layer, an unvulcanized laminated body sample of a 7-layer
structure of [rubber composition layer A--undegraded reinforcing
member layer--rubber composition layer B--undegraded reinforcing
member layer--rubber composition layer C--undegraded reinforcing
member layer--rubber composition layer D] was prepared. This
unvulcanized laminated body sample was vulcanized in a
predetermined mold at 148.degree. C. for a time that is 1.5 times
the t.sub.c(90) determined as mentioned above, left to stand
overnight at room temperature, so as to obtain a vulcanized
laminated body sample I.
[0109] Moreover, with the same method as mentioned below, an
unvulcanized laminated body sample of a 7-layer structure of
[rubber composition layer A--degraded reinforcing member
layer--rubber composition layer B--degraded reinforcing member
layer--rubber composition layer C--degraded reinforcing member
layer--rubber composition layer D] was prepared, so as to obtain a
vulcanized laminated body sample II with the same method as
mentioned above.
[0110] The aforementioned rubber composition layers A to D were
each prepared from a rubber composition of the same type.
[0111] By using these laminated body samples I and II, adhesiveness
between the rubber composition layers and the reinforcing member
layer was evaluated according to the following procedure.
[0112] (Peel Test of Rubber Composition Layer and Reinforcing
Member Layer)
[0113] The aforementioned laminated body sample was cut into a
width of 25 mm in the warp direction, and then cuts of 10 mm to 20
mm were opened with a knife on a part of the rubber composition
layer B. A peel test was performed with an "Auto Rubber Universal
Testing Machin AC-10 kN" manufactured by TSE Corporation, in which
the sample was peeled off from the cut portions. Here, a peel
strength in this test (N/25 mm) was measured at a peel angle of
90.degree. and a peel speed of 50 mm/min. Then, adhesiveness and
the peel operability of the laminated body samples I and II were
evaluated according to the following. Tables 1 to 3 list the
results of this evaluation.
[0114] --Evaluation of Adhesiveness-- [0115] Larger than 100 N/25
mm . . . excellent [0116] 100 to 80 N/25 mm . . . good [0117]
Smaller than 80 N/25 mm . . . poor
[0118] --Evaluation of Peel Operability-- [0119] 300 N/25 mm or
less . . . excellent [0120] Larger than 300 N/25 mm . . . poor
[0121] A rubber amount remaining on the reinforcing member layer
after this test (rubber attachment amount) was evaluated according
to the method described below. Namely, among the two reinforcing
member layers adjacent the peeled rubber composition layer B, with
respect to a reinforcing member layer which is judged by observing
as having a smaller rubber attachment amount, its rubber attachment
surface was imaged as a sample photo. Next, the imaged sample photo
was subjected to image thresholding into a rubber component and a
reinforcing member layer component and area calculation with an
image processing software, where the case in which the rubber
remained in an area larger than 60% was evaluated as excellent, the
case in which the rubber remained in an area of 60% to 40% as good,
and the case in which the rubber remained in an area smaller than
40% as poor. Tables 1 to 3 list the results of this evaluation.
[0122] For reference, FIG. 1A illustrates a schematic view of a
peeled surface in a test using the laminated body sample I of
Example 1, and FIG. 1B illustrates a schematic view of a peeled
surface in a test using the laminated body sample II of Example 1.
Similarly, FIG. 2A illustrates a schematic view of a peeled surface
in a test using the laminated body sample I of Comparative Example
2, and FIG. 2B illustrates a schematic view of a peeled surface in
a test using the laminated body sample II of Comparative Example 2.
Moreover, similarly, FIG. 3A illustrates a schematic view of a
peeled surface in a test using the laminated body sample I of
Comparative Example 6, and FIG. 3B illustrates a schematic view of
a peeled surface in a test using the laminated body sample II of
Comparative Example 6. Here, a darker color of the peeled surface
indicates that more rubber composition remained, and indicates
excellent adhesiveness without occurrence of interfacial peeling
between the rubber composition layer and the reinforcing member
layer.
TABLE-US-00001 TABLE 1 Compar- Compar- Compar- Compar- Compar-
Compar- ative ative Exam- Exam- Exam- Exam- ative ative ative ative
Example Example ple ple ple ple Example Example Example Example 1 2
1 2 3 4 3 4 5 6 Natural rubber *1 35 35 35 35 35 35 35 35 35 35
Styrene-butadiene rubber 60 60 60 60 60 60 60 60 60 60 Reclaimed
Diene based 5 5 5 5 5 5 5 5 5 5 rubber *3 rubber Carbon black 2.5
2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Others 2.5 2.5 2.5 2.5 2.5 2.5
2.5 2.5 2.5 2.5 Calcium carbonate 1 *4 82 82 82 82 82 82 82 82 0 5
Carbon black 1 *8 44.0 42.0 41.0 40.5 39.5 39.2 39.0 38.0 40.0 40.0
Carbon black 2 *9 0 0 0 0 0 0 0 0 0 0 Carbon black 3 *10 0 0 0 0 0
0 0 0 0 0 Wet silica 1 *11 0 2.0 3.0 3.5 4.5 4.8 5.1 6.0 4.0 4.0
Wet silica 2 *12 0 0 0 0 0 0 0 0 0 0 Wet silica 3 *13 0 0 0 0 0 0 0
0 0 0 Wet silica 4 *14 0 0 0 0 0 0 0 0 0 0 Wet silica 5 *15 0 0 0 0
0 0 0 0 0 0 Wet silica 6 *16 0 0 0 0 0 0 0 0 0 0 Dry silica 1 *17 0
0 0 0 0 0 0 0 0 0 Evaluation of vulcanization Excel- Excel- Excel-
Good Good Good Poor Poor Good Good time lent lent lent Peel test
Peel strength 150 153 153 154 158 161 162 165 335 311 on rubber
(N/25 mm) composition Evaluation of Excel- Excel- Excel- Excel-
Excel- Excel- Excel- Excel- Excel- Excel- layer and adhesiveness
lent lent lent lent lent lent lent lent lent lent undegraded
Evaluation of Excel- Excel- Excel- Excel- Excel- Excel- Excel-
Excel- Poor Poor reinforcing peel operability lent lent lent lent
lent lent lent lent member Evaluation of Excel- Excel- Excel-
Excel- Excel- Excel- Excel- Excel- Good Excel- layer rubber
attachment lent lent lent lent lent lent lent lent lent Peel test
Peel strength 71 78 112 115 123 126 129 133 305 280 on rubber (N/25
mm) composition Evaluation of Poor Poor Excel- Excel- Excel- Excel-
Excel- Excel- Excel- Excel- layer and adhesiveness lent lent lent
lent lent lent lent lent degraded Evaluation of Excel- Excel-
Excel- Excel- Excel- Excel- Excel- Excel- Poor Excel- reinforcing
peel operability lent lent lent lent lent lent lent lent lent
member Evaluation of Poor Good Excel- Excel- Excel- Excel- Excel-
Excel- Good Good layer rubber attachment lent lent lent lent lent
lent
TABLE-US-00002 TABLE 2 Compar- Exam- Exam- Exam- Exam- ative Exam-
Exam- Exam- Exam- Exam- Exam- ple ple ple ple Example ple ple ple
ple ple ple 5 6 7 8 7 9 10 11 12 13 14 Natural rubber *1 35 35 35
35 35 35 35 35 35 35 35 Styrene-butadiene rubber 60 60 60 60 60 60
60 65 65 65 65 Reclaimed Diene based 5 5 5 5 5 5 5 0 0 0 0 rubber
*3 rubber Carbon black 2.5 2.5 2.5 2.5 2.5 2.5 2.5 0 0 0 0 Others
2.5 2.5 2.5 2.5 2.5 2.5 2.5 0 0 0 0 Calcium carbonate 1 *4 10 20 40
120 140 82 82 82 82 82 10 Carbon black 1 *8 40.0 40.0 40.0 40.0
40.0 40.0 40.0 41.0 40.5 39.2 40.0 Carbon black 2 *9 0 0 0 0 0 0 0
0 0 0 0 Carbon black 3 *10 0 0 0 0 0 0 0 0 0 0 0 Wet silica 1 *11
4.0 4.0 4.0 4.0 4.0 0 0 3.0 3.5 4.8 4.0 Wet silica 2 *12 0 0 0 0 0
4.0 0 0 0 0 0 Wet silica 3 *13 0 0 0 0 0 0 4.0 0 0 0 0 Wet silica 4
*14 0 0 0 0 0 0 0 0 0 0 0 Wet silica 5 *15 0 0 0 0 0 0 0 0 0 0 0
Wet silica 6 *16 0 0 0 0 0 0 0 0 0 0 0 Dry silica 1 *17 0 0 0 0 0 0
0 0 0 0 0 Evaluation of vulcanization Good Good Good Good Good Good
Good Excel- Good Good Good time lent Peel test Peel strength 282
246 169 111 86 150 147 160 160 161 278 on rubber (N/25 mm)
composition Evaluation of Excel- Excel- Excel- Excel- Good Excel-
Excel- Excel- Excel- Excel- Excel- layer and adhesiveness lent lent
lent lent lent lent lent lent lent lent undegraded Evaluation of
Excel- Excel- Excel- Excel- Excel- Excel- Excel- Excel- Excel-
Excel- Excel- reinforcing peel operability lent lent lent lent lent
lent lent lent lent lent lent member Evaluation of Excel- Excel-
Excel- Excel- Excel- Excel- Good Excel- Excel- Excel- Excel- layer
rubber attachment lent lent lent lent lent lent lent lent lent lent
Peel test Peel strength 259 239 168 108 75 123 108 117 125 128 265
on rubber (N/25 mm) composition Evaluation of Excel- Excel- Excel-
Excel- Poor Excel- Excel- Excel- Excel- Excel- Excel- layer and
adhesiveness lent lent lent lent lent lent lent lent lent lent
degraded Evaluation of Excel- Excel- Excel- Excel- Excel- Excel-
Excel- Excel- Excel- Excel- Excel- reinforcing peel operability
lent lent lent lent lent lent lent lent lent lent lent member
Evaluation of Excel- Excel- Excel- Excel- Excel- Good Good Excel-
Excel- Excel- Excel- layer rubber attachment lent lent lent lent
lent lent lent lent lent
TABLE-US-00003 TABLE 3 Compar- Compar- Compar- Exam- ative ative
Exam- ative Exam- Exam- Exam- Exam- ple Example Example ple Example
ple ple ple ple 15 8 9 16 10 17 18 19 20 Natural rubber *1 35 35 35
35 35 35 35 35 35 Styrene-butadiene rubber 65 60 60 60 60 60 60 60
60 Reclaimed rubber *3 Diene based rubber 0 5 5 5 5 5 5 5 5 Carbon
black 0 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Others 0 2.5 2.5 2.5 2.5
2.5 2.5 2.5 2.5 Calcium carbonate 1 *4 120 82 20 20 20 20 82 82 82
Carbon black 1 *8 40.0 40.0 0 0 0 0 39.5 39.5 39.5 Carbon black 2
*9 0 0 44.0 40.0 0 0 0 0 0 Carbon black 3 *10 0 0 0 0 44.0 40.0 0 0
0 Wet silica 1 *11 4.0 0 0 4.0 0 4.0 0 0 0 Wet silica 2 *12 0 0 0 0
0 0 0 0 0 Wet silica 3 *13 0 0 0 0 0 0 0 0 0 Wet silica 4 *14 0 0 0
0 0 0 4.5 0 0 Wet silica 5 *15 0 0 0 0 0 0 0 4.5 0 Wet silica 6 *16
0 0 0 0 0 0 0 0 4.5 Dry silica 1 *17 0 4.0 0 0 0 0 0 0 0 Evaluation
of vulcanization Good Excel- Excel- Good Excel- Good Good Good Good
time lent lent lent Peel test Peel strength 111 150 245 259 310 282
155 151 150 on rubber (N/25 mm) composition Evaluation of Excel-
Excel- Excel- Excel- Excel- Excel- Excel- Excel- Excel- layer and
adhesiveness lent lent lent lent lent lent lent lent lent
undegraded Evaluation of Excel- Excel- Excel- Excel- Poor Excel-
Excel- Excel- Excel- reinforcing peel operability lent lent lent
lent lent lent lent lent member Evaluation of Excel- Excel- Excel-
Excel- Excel- Excel- Excel- Excel- Excel- layer rubber attachment
lent lent lent lent lent lent lent lent lent Peel test Peel
strength 108 74 78 168 75 200 119 108 98 on rubber (N/25 mm)
composition Evaluation of Excel- Poor Poor Excel- Poor Excel-
Excel- Excel- Good layer and adhesiveness lent lent lent lent lent
degraded Evaluation of Excel- Excel- Excel- Excel- Excel- Excel-
Excel- Excel- Excel- reinforcing peel operability lent lent lent
lent lent lent lent lent lent member Evaluation of Excel- Poor Poor
Excel- Poor Excel- Good Good Good layer rubber attachment lent lent
lent
TABLE-US-00004 TABLE 4 Example Example Example Example 21 22 23 24
Natural rubber *1 35 35 35 35 Styrene-butadiene rubber 60 60 60 60
Reclaimed rubber *3 Diene based rubber 5 5 5 5 Carbon black 2.5 2.5
2.5 2.5 Others 2.5 2.5 2.5 2.5 Calcium carbonate 1 *4 82 0 0 0
Calcium carbonate 2 *5 0 82 0 0 Calcium carbonate 3 *6 0 0 82 0
Calcium carbonate 4 *7 0 0 0 82 Carbon black 1 *8 40.0 40.0 40.0
40.0 Carbon black 2 *9 0 0 0 0 Carbon black 3 *10 0 0 0 0 Wet
silica 1 *11 4.0 4.0 4.0 4.0 Wet silica 2 *12 0 0 0 0 Wet silica 3
*13 0 0 0 0 Wet silica 4 *14 0 0 0 0 Wet silica 5 *15 0 0 0 0 Wet
silica 6 *16 0 0 0 0 Dry silica 1 *17 0 0 0 0 Evaluation of
vulcanization time Good Good Good Good Evaluation of film thickness
stability Excellent Excellent Good Excellent Peel test on rubber
Peel strength (N/25 mm) 157 143 166 155 composition layer and
Evaluation of adhesiveness Excellent Excellent Excellent Excellent
undegraded reinforcing Evaluation of peel operability Excellent
Excellent Excellent Excellent member layer Evaluation of rubber
attachment Excellent Excellent Excellent Excellent Peel test on
rubber Peel strength (N/25 mm) 120 107 110 118 composition layer
and Evaluation of adhesiveness Excellent Excellent Excellent
Excellent degraded reinforcing Evaluation of peel operability
Excellent Excellent Excellent Excellent member layer Evaluation of
rubber attachment Excellent Good Good Excellent *1 Natural rubber .
. . Grade; No. RSS-4 2 Styrene-butadiene rubber . . . "TAFDEN
2000R", manufactured by Asahi Kasei Chemicals Corporation, cis-1,4
bond content in butadiene monomer unit: 90% or less *3 Reclaimed
rubber . . . 50 mass % of diene based rubber, 25 mass % of carbon
black, 25 mass % of others (other than rubber component, carbon
black, wet silica, calcium carbonate, and dry silica) *4 Calcium
carbonate 1 . . . "NS#100", manufactured by Nitto Funka Kogyo K.
K., average primary particle size: 2.1 .mu.m *5 Calcium carbonate 2
. . . "NS#200", manufactured by Nitto Funka Kogyo K. K., average
primary particle size: 14.8 .mu.m *6 Calcium carbonate 3 . . .
"SOFTON 3200", manufactured by Shiraishi Calcium Kaisha, Ltd.,
average primary particle size: 0.7 .mu.m *7 Calcium carbonate 4 . .
. "NS#500", manufactured by Nitto Funka Kogyo K. K., average
primary particle size: 4.4 .mu.m *8 Carbon black 1 . . .
"ASAHI#52", manufactured by Asahi Carbon Co., Ltd., nitrogen
adsorption BET specific surface area: 28 m.sup.2/g *9 Carbon black
2 . . . "SHO-BLACK N330", manufactured by Cabot Japan K. K.,
nitrogen adsorption BET specific surface area: 78 m.sup.2/g *10
Carbon black 3 . . . "SEAST 6", manufactured by Tokai Carbon Co.,
Ltd., nitrogen adsorption BET specific surface area: 119 m.sup.2/g
*11 Wet silica 1 . . . "Nipsil AQ", manufactured by Tosoh Silica
Corporation, nitrogen adsorption BET specific surface area: 205
m.sup.2/g *12 Wet silica 2 . . . "Nipsil SS-50F", manufactured by
Tosoh Silica Corporation, nitrogen adsorption BET specific surface
area: 82 m.sup.2/g *13 Wet silica 3 . . . "Nipsil SS-70",
manufactured by Tosoh Silica Corporation, nitrogen adsorption BET
specific surface area: 42 m.sup.2/g *14 Wet silica 4 . . .
"ULTRASIL VN3", manufactured by Evonic Degussa Corporation,
nitrogen adsorption BET specific surface area: 175 m.sup.2/g *15
Wet silica 5 . . . "Nipsil NA", manufactured by Tosoh Silica
Corporation, nitrogen adsorption BET specific surface area: 135
m.sup.2/g *16 Wet silica 6 . . . "Nipsil ER", manufactured by Tosoh
Silica Corporation, nitrogen adsorption BET specific surface area:
95 m.sup.2/g *17 Dry silica 1 . . . "AEROSIL 130", manufactured by
Nippon Aerosil Co., Ltd., nitrogen adsorption BET specific surface
area: 130 m.sup.2/g
[0123] According to Tables 1 to 4, the disclosed rubber
composition, which is obtainable by compounding a rubber component
containing a diene based rubber, a wet silica, a carbon black, and
calcium carbonate, where the compounding amount of the wet silica
is 3 parts by mass or more and less than 5 parts by mass per 100
parts by mass of the diene based rubber, and the compounding amount
of the calcium carbonate is 10 parts by mass or more and 120 parts
by mass or less per 100 parts by mass of the diene based rubber,
brought a peel strength of 80 N/25 mm or more, and had a larger
amount of rubber remaining on the reinforcing member layer, in both
the peel test of the layer containing this rubber composition and
the undegraded reinforcing member layer and the peel test of the
layer containing this rubber composition and the degraded
reinforcing member layer. Therefore, it is understood that the
disclosed rubber composition has excellent adhesiveness to an
undegraded reinforcing member and excellent adhesiveness to a
reinforcing member in environmental degradation. This fact is
clarified as well from the darker color of the peeled surfaces in
both FIG. 1A and FIG. 1B (on the other hand, the peeled surfaces in
FIG. 2B and FIG. 3B appear lighter). Moreover, as indicated in
Tables 1 to 4, in the aforementioned peel test, the disclosed
rubber composition has a peel strength of 300 N/25 mm or less, and
thus has high peel operability with an undegraded reinforcing
member and a reinforcing member in environmental degradation.
Further, the rubber composition needs a shorter time for
vulcanization, which indicates high productivity.
INDUSTRIAL APPLICABILITY
[0124] According to this disclosure, it is possible to provide a
rubber composition having excellent adhesiveness to a reinforcing
member, particularly a reinforcing member in environmental
degradation, and capable of bringing high peeling operability
therewith. Moreover, according to this disclosure, it is possible
to provide a laminated body using the aforementioned rubber
composition and capable of improving durability of a rubber
product, and a conveyor belt using the aforementioned laminated
body and having high durability.
* * * * *